Apoplastic and symplastic uptake of phenanthrene in wheat roots. (February 2018)

• Record Type: Journal Article
• Authors: Zhan, Xinhua; Zhu, Mandang; Shen, Yu; Yue, Le; Li, Jinfeng; Gardea-Torresdey, Jorge L.; Xu, Guohua
• Is Part Of: Environmental pollution. Volume 233(2018)
• Page Start: 331
• Page End: 339
• Publication Date: 2018-02
• Subjects: Polycyclic aromatic hydrocarbons -- Apoplast -- Symplast -- Phenanthrene -- Wheat root uptake; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2017.10.056
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The contamination of agricultural crops by polycyclic aromatic hydrocarbons (PAHs) has drawn considerable attention due to their carcinogenicity, mutagenicity, and toxicity. However, the uptake process of PAHs in plant roots has not been clearly understood. In this work, we first study the radial uptake of phenanthrene in hydroculture wheat roots by vacuum-infiltration-centrifugation method. The concentration-dependent kinetics of apoplastic and symplastic uptake at phenanthrene concentrations of 0–6.72 μM for 4 h can be described with the Langmuir and Michaelis-Menten equations, respectively; whereas, their time-dependent kinetics at 5.60 μM phenanthrene for 36 h follow the Elovich equation. The apoplastic and symplastic uptake increases with temperature of 15–35 °C. The apparent Arrhenius activation energies for apoplastic and symplastic uptake are 77.5 and 9.39 KJ mol −1, respectively. The symplastic uptake accounts for over 55% of total phenanthrene uptake, suggesting that symplast is the dominant pathway for wheat root phenanthrene uptake. Larger volume of symplast in roots and lower activation energy lead to the greater contribution of symplast to total uptake of phenanthrene. Our results provide not only novel insights into the mechanisms on the uptake of PAHs by plant roots, but also the help to optimize strategies for crop safety and phytoremediation of PAH-contaminated soil/water. Graphical abstract: Image 1 Highlights: Apoplast and symplast are involved in phenanthrene uptake by wheat roots. The Elovich equation can describe time-dependent apoplastic and symplastic uptake. The apparent activation energy for symplast is lower than that for apoplast. The contribution of symplast to total root uptake is greater than that of apoplast. Abstract : The greater contribution of symplast to total root uptake of phenanthrene results from its larger volume in roots and lower activation energy.